Constipation is a major problem for elderly people in this country. According to a survey spported by the current TNH Award, 31% of community-dwelling elderly over age 65 suffer from constipation and 19% use laxatives regularly. In contrast, only 4% of young factory workers in another survey reported constipation. Though rarely contributing to mortality, constipation should be recognized as a major cause of morbidity in the elderly because of its prevalence, the discomfort it causes, its association with urinary and fecal incontinence (the latter contributing to increased urinary tract infections), and the propensity of sufferers to self-medicate. Yet little is known about the causes of constipation in the elderly. In fact, there are discrepancies in how patients and physicians define constipation. Patients often-point to difficulty in evacuating stool, while physicians usually define it in terms of frequency and consistency of stools. This study will investigate (a) which of three types of constipation - atonic colon, irritable colon or outlet obstruction, defined by clinical radiographic and manometric criteria account for the high prevalence of constipation in the elderly, and (b) the relationship of exercise and dietary fiber intake to each of these forms of constipation. Specific hypotheses are: (1) Exercise will be associated with lower rates of atonic colon and outlet obstruction, but not irritable colon type constipation. Three populations of elderly - athletes, ambulatory patients, and institutionalized patients will be compared, statistically controlling for mental status, gender, and diet. (2) The intervention of increasing exercise in constipated ambulatory elderly will reduce atonic and outlet obstruction constipation. Conversely, deconditioning will increase the prevalence of atonic and outlet obstruction constipation. (3) Dietary fiber intake will be inversely correlated with the prevalence of all types of constipation after controlling for exercise level, mental status, and gender. (4) The intervention of increasing fiber intake by 25 grams per day will reduce the prevalence of all types of constipation.